Recently mounted a 1980 70HP Evinrude on my boat. The motor had not been run for 3 years and probably not much before I got it. Found a 60yo OMC mechanic that still worked occasionally for his kids and had him get it started. 130 psi +/- 5 in all 3 cylinders. The guy changed impeller,new fluid in lower unit, replaced the starter solenoid and got it started. Ran OK on muffs but unfortunately all I had was 2 yo gas. We put a gas treatment in the tank but not good stuff. First trip it started and there was a real hesitancy when I advanced the throttle. Stalled at slow speed and idle. I expected that from reading these forums.
Dumped the old gas, added Mercury Quickare but unfortunately I had run the gas out of the carbs before reading here that is not a good idea. Second trip, idled for a while at marina and as I increased the throttle out of the marina the motor coughed and backfired for what was probably 30 seconds, then pow, a big plume of smoke and it ran fine. There was still a hesitancy in mid throttle but when it kicked in it ran fine. We were drift fishing so periodically had to start the motor and run back to the stating point. Always started, still had the hesitation, but for once didn't stall in neutral. At dock and later on loading trailer did better than expected but it did stall going from forward to reverse.
Third trip, started, advanced into forward without stalling, and accelerated to half speed and stayed there for maybe 10 seconds, then kicked in. No backfires and no smoke this time. After a day fishing the motor started, accelerated all the way thru the throttle advance without hesitation, and ran better than ever. At the marina and later loading the boat on the trailer it shifted between forward and reverse without stalling. To date I have run 2 gallon of bad gas and 4 gallons of good gas with a cleaner thru the motor.
Other info - I do not have a tach which I know will eventually be necessary. The mechanic guy has specifically asked me about a tach twice. His advice was to keep running it with a good cleaner before going after the carbs.
My concern - on the second trip it seemed like it was firing on 2 cylinders and with the pow the third kicked in. From what I have read it is not good to do this long because the cylinder may not be getting oil. If this happens again is it something that should turn me around. Am I risking what otherwise seems like a good motor by trying to treat the carbs with a cleaner and putting off the rebuild until after the season ends. Last time I took on a project late in the season I never did get back on the water. Thanks for any advice.
Dumped the old gas, added Mercury Quickare but unfortunately I had run the gas out of the carbs before reading here that is not a good idea. Second trip, idled for a while at marina and as I increased the throttle out of the marina the motor coughed and backfired for what was probably 30 seconds, then pow, a big plume of smoke and it ran fine. There was still a hesitancy in mid throttle but when it kicked in it ran fine. We were drift fishing so periodically had to start the motor and run back to the stating point. Always started, still had the hesitation, but for once didn't stall in neutral. At dock and later on loading trailer did better than expected but it did stall going from forward to reverse.
Third trip, started, advanced into forward without stalling, and accelerated to half speed and stayed there for maybe 10 seconds, then kicked in. No backfires and no smoke this time. After a day fishing the motor started, accelerated all the way thru the throttle advance without hesitation, and ran better than ever. At the marina and later loading the boat on the trailer it shifted between forward and reverse without stalling. To date I have run 2 gallon of bad gas and 4 gallons of good gas with a cleaner thru the motor.
Other info - I do not have a tach which I know will eventually be necessary. The mechanic guy has specifically asked me about a tach twice. His advice was to keep running it with a good cleaner before going after the carbs.
My concern - on the second trip it seemed like it was firing on 2 cylinders and with the pow the third kicked in. From what I have read it is not good to do this long because the cylinder may not be getting oil. If this happens again is it something that should turn me around. Am I risking what otherwise seems like a good motor by trying to treat the carbs with a cleaner and putting off the rebuild until after the season ends. Last time I took on a project late in the season I never did get back on the water. Thanks for any advice.